Predetermined depth-maintaining, selfpropelled model submarine



May 29, 1962 F. G. PREsNELL PREDETERMINED DEPTH-MAINTAINING, SELF-PROPELLED MODEL SUBMARINE Filed April l, 1960 rraewsy SNN . I Il Il Il in. ll

United States 'Ihis invention deals generally with toys and particularly with a self-propelled model submarine.

A general `object of the invention is to provide a selfpropelled model submarine which automatically dives from the surface to a predetermined `depth and then cruises submerged at this depth.

Another object of the invention is to provide a selfpropelled model submarine in which the longitudinal `trim of the model is automatically adjusted so that the latter assumes a realistic dive angle for submerging and gradually returns to a horizontal attitude for cruising submerged at the predetermined depth.

An object of the invention closely associated with the foregoing object is to provide a self-propelled model submarine of the character described in which the automatic `trim control means operate to maintain the model at the predetermined depth with minimum hunting movement of the model -about this depth.

A further object of the invention is to provide a selfpropelled model submarine of the character described which is ideally suited -for marketing as a kit to be assembled by the purchaser.

Yet a further object of the invention is to provide a self-propelled model submarine which is simple in construction, easy to use, and otherwise especially well suited to its intended purposes.

Other objects, advantages, and -features of the invention will become readily apparent as the description proceeds.

Brieiiy, the objects of the invention are attained by providing a buoyant hull which initially floats at the surface of water and propulsion means on the hull for propelling the model forwardly in the water. Means are provided for causing the model to assume a bow-down or dive attitude while it is at the surface so that forward propulsion of the model causes the latter to submerge.

Automatic fore and aft trim control of the model, for causing the latter to seek and run submerged Iat a predetermined depth, is achieved by a pressure-responsive trim control means on the hull. 'Ihis means adjusts the fore and aft trim of the hull in response to changes in external water pressure in such a way that the model gradually assumes a horizontal attitude `as it submerges and then cruises submerged in this horizontal attitude at a predetermined depth. The model continues to run at this predetermined `depth until retrieved or until the propulsion means stop whereupon the overall buoyancy of the model brings thelatter to the surface.

A better understanding of the invention may be had from the following detailed description thereof, taken in connection with the annexed drawing, wherein:

FIG. l is a perspective view of the present model submarine;

FIG. 2 is an enlarged, longitudinal section through the model;

FIG. 3 is a section taken along line 3 3 in lFIG. 2;

PIG. 4 is a section taken along line 4-'4 in FIG. 2;

FIG. 5 is a view, in longitudinal section, of the after end of a modified model submarine according to the invention; and

FIG. 6 is a section taken along line 6-6 in FIG. 5.

The model submarine illustrated in FIGS. 1-4 comprises a hollow hull 10 constructed of suitable material, such as polystyrene plastic, and includes ya forward secatent O tion 12, an intermediate motor -section 14, and a rear or stern section 16. This hull is shaped to ysimulate an actual submarine and for this purpose is provided with a simulated conning tower 18, periscope 20, forward planes 22, stern planes 24, and rudders 26.

Within the hull are `three partitions 28, 30l and 32. The forward partition 28 extends generally lengthwise of the hull and ydivides the interior of the forward hull section 12 into a lower buoyancy chamber 34 and an upper buoyancy chamber 36. The remaining partitions 30 and 32 are located -between the -forward hull section 12 and the mot-or section 14 and between the motor section and stern section 16, respectively. The space 38 between these latter partitions 30 and 32 communicates with the upper forward buoyancy chamber 36 through an opening 40 in the upper end of partition 30 and with a buoyancy chamber 42 in the stern section 16 through an opening 44 in the upper end yof the partition 32.

The hull has a forward bottom opening y46 to the lower forward buoyancy chamber 34 and two upper vent openings 48 to the latter chamber. These vent openings are located at opposite -sides of the hull, closely adjacent the partitions 28 and 30, and partition 28 is downwardly convex in transverse section, as shown, to permit substantially complete flooding of the chamber 34 when the model submerges, Ias will be presently more -fully discussed. The hull has a second bottom 'opening 50 to the stern buoyancy chamber 42. This opening is 1ocated adjacent the forward end of the chamber, close to the partition 32, for reasons soon to be seen.

Suitably mounted within the motor section 1'4 of the hull is a small electric motor 52. The shaft 54 of this motor is connected to a propeller shaft S6 by -a short flexible tube 58. Partition 32 has a central, rearwardly projecting hub y60 into which the tube 58 extends.

Propeller shaft 56 is rotatable within a bearing sleeve 62. The forward end of this bearing sleeve is presstted into the end of the partition hub 60 and the rear end of the sleeve is press-fitted into the end of the stern section 16. Fixed to the rear end of the propeller shaft is a propeller 64. Y

The flexible tube connection 58 between the propeller and moto-r shafts is desirable since it accommodates slight misalignment of these shafts. It may also be desirable to place a short spacer shaft 66 between the propeller and motor shafts in order to maintain a clearance space at 68 between the stern section and propeller.

Motor 52 is powered by a flashlight' battery 70 located within the lower chamber 34 of the forward hull section 12. This battery may be mounted in any convenient way, such as by a spring clip 72 attached at 74 to the underside of the partition 28. This clip engages the end of the battery to urge the button 76 at the top of the battery into a socket 78 on the front side of partition 30. The motor terminals are connected to the battery by wires 80, one of which attaches to the cli-p '72 and the other of which attaches to a contact 82 engaged by the battery button 76. The wires are sealed in any suitable way to the partitions Where they pass through the latter.

The battery is removed and replaced through an opening 84- in the bottom of the hull which is closed by a removable hatch 8'6. As shown most clearly in FIGS. l and 4, this hatch is curved to match the hull and has edges which abut the edges of the hull opening 84, when the hatch is closed. The hatch is held in its closed position by a rear lip 88 on the hatch which engages over the forward edge of the motor section 14 and by forward ears 90 on the hatch which snap into place behind inwardly curved hull portions at the forward upper end of the hull opening 84 in the manner illustrated best in FIG. 4.

Ballast for the model may be provided in any convenient way. For example, a ballast washer 92 may be placed over a circular boss 94 on the inside bottom of the hull. The upper end of this boss is expanded over the washer to retain the latter in position.

As mentioned earlier, the model of this invention is adapted for marketing as a kit to Ibe assembled by the purchaser. For this reason, the hull of the model submarine illustrated in the drawing is composed of several separate molded plastic pieces which are easily assembled and cemented together. Thus, it will be observed that the three yhull sections 12, 14 and 16 are separate pieces provided with interlitting ends which are easily joined by suitable plastic cement. The partition 3i) is a separate piece which fits in the front end of the motor section 14. This partition is preferably cemented in position to prevent water leakage between chambers 34 and 38.

The forward hullsection 12 is, itself, composed of a top half 12a and a bottom half 12b which have abutting edges cemented together and the partition 2S which is cemented to the top half 12a and to p-artition 3i). The hatch 86, of course, is a separate piece which snaps into position in the hull opening 84.

The battery clip 72 and ballast washer 9L. may be easily Lsecured in position by using a .heated screw driver or the like to expand the plastic material of the bosses 74 and 94 over these parts. The motor S2 is mounted in the motor section 14 in any convenient manner, as already noted.

When the model is rst placed in water `with its motor operating, it assumes an initial generally horizontal attitude and is propelled along the water surface. Immediately upon placingrthe model in water, water ilowsinto the forward buoyancy chamber 34 through the forward, bottom hull opening 46, the air in the chamber escaping through the vent openings 48. The air in the rearbuoyancy cham-ber 42 cannot escape except through the motor chamber 3S intoV the upper forward buoyancy chamber 36. At rst, therefore, no appreciable quantity of water enters the after chamber through the rear hull opening '50 since it is held back by the trapped air in the communicating chambers 36, 38 and 42.

Flooding of the forward chamber 34 therefore results in the model assuming a bow-down or dive attitude. Forward propulsion of the model in this dive attitude causes it to submerge in a realistic-fashion.

As the depth of the model below the surface incre-ases, the increasing water pressure compresses the air in the communicating chambers 42, 38 and 36 and the water level in the rear buoyancy chamber 42 rises. This, in effect, reduces the water displacement volume of the after hull section 16 and, therefore, its buoyant force so that the model gradually assumes a horizontal attitude as it submerges.

The model is designed so that at some predetermined depth, say a depth of one or two feet, the effective displacement Volume of the after hull section is reduced sufficiently to bring the model to a horizontal attitude. The model then cruises submerged at this predetermined depth. Thus, if the model rises, water is expelled from the after section 16 to increase the effective displacement volume of and the Abuoyant force on the latter section. This causes the model to assume a slight bow-down attitude and dive deeper. If the model goes below the predetermined depth, additional water enters the after section 16 to decrease its effective displacement volume and the buoyant force thereon. This causes the model Vto assume a slight bow-up attitude and rise toward the predetermined depth. The model continues to operate in this fashion until retrieved or until the battery 70- wears out whereupon the overall buoyant forceon the model brings the latter to the surface.

From Vthis discussion, it is evident that the floodable forward buoyancy chamber 34 :andl the after buoyancy chamber 42 provide an automatic trim control or centerof-buoyancy positioning means which operates to cause the model to automatically dive from the surface to a predetermined-depth and cruise submerged at this depth.

It ywill be immediately evident that means other than the illustrated floodable buoyancy chamber .may be used to cause the model to assume atdive attitude at the surface. For example, the model may be permanently trimmed in some way for this purpose. The illustrated iloodable chamber is desirable, however, since it achieves a more realistic diving action. Also, the length of time the model remains on the surface may be varied by changing the size of the hull openings to the forward chamber 34.

It is further evident that the air contained in the after section 16 functions as an elastically compressible, pressure-responsive, variable buoyancy or variable displacement means. The effective 4water displacement volume of this means and, therefore, the buoyant force on the rear end of thehull vary inversely wit-h water pressure to cause the model to seek and cruise submerged `at a predetermined depth. Communication of the after section buoyan-cy chamber 42 with the motor section and forward section chambers 3S and 36 is advantageous since it appreciably increases the volume of air on which external water pressure acts to achieve the pressure-responsive, Variable displacement action. This increased volume of air renders the variable displacement means sufficiently sensitive to operate very satisfactorily at realtively shallow depths of one to two feet, so that the model can be easily retrieved from the side of a swimming pool, for example.

Since the pressure in the motor chamber 38 is slightly in excess of external water pressure to start with and only slightly less than external Water pressure even when the after chamber 42 is almost completely Hooded, there is little, if any, leakage of water into the motor chamber between the propeller shaft 56 and its bearing sleeve 58. Also, no water will ordinarily enter the motor chamber through the rear partition opening 44 since the Water level in the after chamber 42 will normally not rise to the opening. Any water which does leak into either the motor chamber or the upper forward buoyancy chamber 36 can be easily removed by turning the model upside down and inclining it so that the water runs to the after chamber through the partition openings 40 and 44.

While, as just mentioned, water will normally not enter the motor chamber, the motor 52 should be of a type which is not damaged by water. Most of the small, commercially available motors are suitable for use in the model if they are provided with stainless steel or other non-corrosive metal shafts. The propeller shaft 56 should also be made of such a non-corrosive metal. This is necessary to avoid possible seizure of these shafts in their bear- 1ngs.

It is obvious that elastically compressible or deformable, variable displacement means other than that described above may be used. A flexible diaphragm mounted in one wal-l of a rear buoyancy chamber in the hull and exposed to external water pressure might be used, for example. FIGS. 5 and 6 illustrate another possible alternative, Since the remainder of the submarine is identical to that just described, only the -variable displacement means have been illustrated in FIGS. 5 and 6.

In this alternative design, the hull has a bottom opening 50 and a top opening 50 to the after section buoyancy chamber s42' so that the chamber fills completely with water. The rear hull partition '32' does not have an opening to the motor chamber 38', as before, so that the after chamber is completely Vsealed off from the motor chamber and the forward upper lbuoyancy chamber (not shown). The motor chamber communicates with the latter buoyancy chamber, as before, however.

The partition 32 has a neck 66) over which is stretched one end of a hollow, elastically deformable buoyant member or sleeve The other end of this sleeve is sealed to a bearing sleeve 62 for the propeller shaft 56. The rear end of this bearingvsleeve is press-.iitted in the rear end of the after hull section 16', as before. The motor shaft 54 is connected to the propeller shaft by a exible tube 58', preferably containing a spacer shaft 66'.

The hull has a removable plug 102'` to permit drainage of any water which leaks into the motor chamber 38.

This modified submarine operates in much the same way as the previous model. That is to say, the forward, lower buoyancy chamber (not shown) of the model fills with water. In the modified submarine, the after chamber 42 also fills with water, as already noted. 'Ihe model is so designed that flooding of the lforward chamber, even with the after chamber 42 completely flooded, causes the model to assume a bow-down or dive attitude so that forward propulsion of the model causes the latter to submerge, as before.

As the depth of the model increases, the increasing water pressure compresses or flattens the elastic tube 100' against its own elasticity and the internal air pressure in the communicating motor chamber 38 and forward, upper buoyancy chamber. 'Ihe effective water displacement volume of the after section 16' and, therefore, its buoyant force are thereby decreased so that the model returns toward a horizontal attitude as it dives. The model is designed so that this decrease in displacement brings the model to a horizontal attitude at some predetermined depth at which it then cruises submerged, as before.

One end of the elastic tube is preferably flattened, as shown in FIG. 6, since otherwise the tube tends to resist deformation until the model dives to an excessive depth at which the tube suddenly, rather than gradually and progressively, collapses. This causes the model to dive and climb in an abrupt and violent manner rather than hold a fairly constant depth. Flattening of the tube, as shown, assures gradual and progressive collapse of the tube and, thus, avoids the above undesirable action.

It is evident, therefore, that the model submarines herein described and illustrated are fully capable of attaining the several objects and advantages set forth.

Numerous modifications in the design and arrangement of parts of the invention are possible, of course, within the spirit and scope of the following claims.

What is claimed is:

1. A model submarine comprising a hollow buoyant hull having transverse partition means defining a rear buoyancy chamber yand a forward buoyancy chamber and a forward longitudinal partition which divides said forward chamber into an upper chamber and a lower chamber, a lower water inlet opening to said lower chamber in the bottom of the hull, an upper vent opening to said lower chamber in the top of the hull, a water inlet opening to said lrear chamber, elastically compressible buoyant means in said rear chamber, said elastically compressible means being exposed to and compressed by the pressure of water entering the rear chamber through aid opening to the rear chamber, propulsion means on the hull to propel the model forwardly in water, and means trimming the hull so that the latter assumes a generally horizontal attitude in water when said lower chamber and said rear chamber are substantially empty of water and also when the lower chamber is substantially Ifilled with water and the rear chamber contains a predetermined volume of water.

2. A model submarine according to claim 1 in which said last-mentioned opening is in the bottom of the hull and said elastically compressible means comprises air in the rear chamber, and a communication between said upper chamber and an upper part of the rear chamber.

3. A model submarine according to claim 1 in which said elastically compressible means comprises a hollow, elastic member in the rear chamber, the interior of said member communicating with said upper chamber.

4. A model submarine comprising ia buoyant hull which initially iioats at the surface of water, propulsion means on the hull for propelling the latter forwardly in the water, means to cause the hull to submerge in response to forward motion thereof through the water, and elastic pressure-responsive, variable water displacement, centerolf-buoyancy positioning means at ythe rear end of the hull, the effective water displacement volume of which varies inversely with external water pressure to cause the center of buoyancy of the hull to move forward-ly along the hull las `the latter submerges, whereby the attitude of the hull gradually changes in the `direction of a bow-up attitude as the hull submerges and the hull finally cruises `submerged at -a relatively constant depth.

5. A model submarine comprising a buoyant hull which initialy floats at the surface of water, propulsion means on the hull for propelling the latter lforwardly in the water, means to cause the hull to submerge in response to Aforward motion thereof through the water, said hull having `a rear, exteriorly communicating chamber, and elastic pressure-responsive, variable water displacement, center-of-buoyancy positioning means Within and exposed to Ithe water pressure in said chamber, the effective water Ydisplacement volume of said latter means v-arying inversely with external water pressure to cause the center of buoyancy of the hull to move `forwardly along the hull as the latter submerges, whereby the attitude of the hull gradually changes in the direction of la bow-up attitude as the hull submerges and the hull finally cruises submerged at a relatively constant depth.

6. A model submarine 'comprising la buoyant hull which initially floats at the surface of water, propulsion means on the hull for propelling the latter forwardly in the water, means to cause the hull to submenge in response to forward motion lthereof through the water, and elastic pressure-responsive, variable water displacement trim control means on the hull comprising a rear buoyancy chamber in the hull communicating to the outside of the latter through an opening in the bottom of the hull and containing air which is compressed by the pressure off water entering the rear chamber through said opening to cause the center of buoyancy of the hull to move forwardly tal-ong the hull as the latter submerges, whereby the attitude of the hull Igradually changes in the direction of a bow-up Iattitude as the hull submerges and the hull finally cruises submerged at a relatively constant depth.

7. A model submarine comprising a buoyant hull which initially floats lat the surface of water, propulsion means on ythe hull `for propelling the latter forwardly in the water, means to cause the hull to submerge in response to forward motion thereof through the water, and elastic pressure-responsive, Variable Water displacement, center-of-buoyancy positioning means on the hull comprising a rear chamber in the hull communicating to .the outside o-f the hull through an opening in the latter, and a hollow, elastic member in the rear chamber which is compressed by the pressure of water entering the rear chamber through said opening to cause the center of buoyancy of the hull to move forwardly along the hull as the 1latter submerges, whereby the attitude of the hull gradually changes in the `direction of .a bow-,up attitude as the hull submerges and the hull finally cruises suba merged at a relatively constant depth1 Y References Cited in the file of this patent UNITED STATES PATENTS 1,271,272 Bunkley July 2, 1918 2,194,564 Middler Mar. 26, 1940 2,515,511 VI-.I -ansen July 18, 1,9151@ 

